I've recently been able to get back to this issue and think I've found the cause. The fs_may_remount_ro() call in file_table.c used to verify that a file system may be remounted RO checks the open file list of the super block for any deleted files and any regular files open for writing. However, tty_open() in ttyio.c moves tty files from this list onto a tty_files list maintained per tty_struct immediately on open, apparently for use in open tty reference counting. So any open deleted terminal devices files are not considered in the remount RO test and the remount is permitted. This then eventually gives ext3 indigestion when it goes to release the deleted file on a now RO file system which should not have been allowed to be remounted RO. I've hacked together a fix which calls into the tty driver and iterates over the open files in all processes, following the pattern __do_SAK() in ttyio.c , and then called this to augment the fs_may_remount_ro() test to include open deleted terminal files, but this approach seems rather heavyweight. Alternative fix suggestions would be quite welcome. Mike Accetta Laurel Networks, Inc. ------- Forwarded Message Date: Fri, 07 Mar 2003 15:16:45 -0500 From: "Michael J. Accetta" <mja@laurelnetworks.com> To: ext3-users@redhat.com Subject: start_transaction: Readonly filesystem error Message: 1 Return-Path: <mail@redhat.com> Delivered-To: ext3-users@listman.redhat.com Sender: ext3-users-admin@redhat.com Precedence: bulk List-Help: <mailto:ext3-users-request@redhat.com?subject=help> List-Post: <mailto:ext3-users@redhat.com> List-Subscribe: <https://listman.redhat.com/mailman/listinfo/ext3-users>, <mail to:ext3-users-request@redhat.com?subject=subscribe> List-Id: EXT3 Users Mailing List <ext3-users.redhat.com> List-Unsubscribe: <https://listman.redhat.com/mailman/listinfo/ext3-users>, <ma ilto:ext3-users-request@redhat.com?subject=unsubscribe> List-Archive: <https://listman.redhat.com/pipermail/ext3-users/> On a 2.4.17 (MontaVista 2.1) kernel using ext3, I recently starting seeing the error EXT3-fs error (device ide1(22,1)) in start_transaction: Readonly filesystem EXT3-fs error (device ide1(22,1)) in ext3_delete_inode: Readonly filesystem on a file system within 10-20 seconds after remounting it r/o. Apparemtly a write is being deferred past the remount point and then runs into problems when it is performed because the file system is now remounted read-only. I've done an lsof in that window and seen an open deleted (special) file so I suspect the bug is in the remount to r/o being permitted while the open deleted file is still in use, rather than ext3. It looks like fs_may_remount_ro() tries to catch open deleted files but is not noticing this case, for some reason. Does this sound like any known bug to anyone? Mike Accetta Laurel Networks, Inc. ------- End of Forwarded Message _______________________________________________ Ext3-users@redhat.com https://listman.redhat.com/mailman/listinfo/ext3-users
